Jorgelina C. Pasqualino

Environmental assessment of urban wastewater reuse: treatment alternatives and applications.

The main function of a Wastewater Treatment Plant is to minimize the environmental impact of discharging untreated water into natural water systems. Also a Wastewater Treatment Plant may get a resource from wastewater carrying out a tertiary treatment on the treated wastewater which can be reused in non-potable applications. Water reuse strategies are intended to address the problem of water scarcity without aggravating other environmental problems, thus reflecting the need of their environmental assessment. In this paper we used Life Cycle Assessment to evaluate different disinfection treatments (chlorination plus ultraviolet treatment, ozonation and ozonation plus hydrogen peroxide) and to assess the environmental advantages and drawbacks of urban wastewater reuse in non-potable applications. To do so, we compared the environmental impacts of producing 1m(3) of water for non-potable uses from reclaimed water, potable water and desalinated water sources. The calculation has used current operating data from a Wastewater Treatment Plant located in the Mediterranean area, although the results can be applied to any other plant with similar technology. The ozonation and ozonation plus hydrogen peroxide disinfection treatment technologies have similar environmental profiles. However most of the indicators are about 50% higher than the ultraviolet disinfection except for the acidification (100% higher) and photochemical oxidation (less than 5%). Non-potable uses (both agricultural and urban uses) of reclaimed water have environmental and economical advantages. Reuse of treated wastewater is particularly beneficial when it can replace desalinated water. Consequently, reclaimed water should be promoted for non-potable uses, when there is scarcity of freshwater.

Environmental performance of construction waste: Comparing three scenarios from a case study in Catalonia, Spain

The main objective of this paper is to evaluate environmental impacts of construction wastes in terms of the LIFE 98 ENV/E/351 project. Construction wastes are classified in accordance with the Life Program Environment Directive of the European Commission. Three different scenarios to current waste management from a case study in Catalonia (Spain) have been compared: landfilling, recycling and incineration, and these scenarios were evaluated by means of Life Cycle Assessment. The recommendations of the Catalan Waste Catalogue and the European Waste Catalogue have been taken into account. Also, the influence of transport has been evaluated. Results show that in terms of the Global Warming Potential, the most environmentally friendly treatment was recycling, followed by incineration and lastly landfilling. According to the influence of treatment plants location on the GWP indicator, we observe that incineration and recycling of construction wastes are better than landfilling, even for long distances from the building site to the plants. This is true for most wastes except for the stony types, than should be recycled close to the building site. In summary, data from construction waste of a Catalan case study was evaluated using the well established method of LCA to determine the environmental impacts.

Environmental assessment of the milk life cycle: The effect of packaging selection and the variability of milk production data

Milk is a very important part of our diet, which is why there is a wide variety of packaging alternatives with considerable local variants on the market. This study assesses the environmental impact of the commonest packaging options on the Spanish market and evaluates (from the point of view of global warming and acidification) the production of the various packaging materials and sizes and their final disposal (landfilling, incineration and recycling). For the two indicators studied (global warming and acidification) larger aseptic carton packages and recycling disposal have the best environmental impact. The global warming and acidification potential of the milk life cycle were also studied: milk production, transport (local conditions), packaging production and packaging disposal. Of the two indicators studied, the milk production stage has the largest impact on the milk life cycle. It should be taken into account that the impact of the milk production stage can vary considerably and has a significant influence on the global warming and acidification potential of the milk life cycle.

Alternatives for Reducing the Environmental Impact of the Main Residue from a Desalination Plant

One of the most important problems today is the scarcity of fresh water safe enough for human, industrial, and agricultural use. Desalination is an alternative source of fresh water supply in areas with severe problems of water availability. Desalination plants generate a huge amount of brine as the main residual from the plant (about 55% of collected seawater). Because of that, it is important to determine the best environmental option for the brine disposal. This article makes a global environmental analysis, under Spanish conditions, of a desalination plant and an environmental assessment of different final brine disposals, representing a range of the most common alternatives: direct disposal, wastewater treatment plant (WWTP) outflow dilution, and dilution with seawater. The environmental profile of the plant operation and a comparison of the brine final disposal alternatives were established by means of the life cycle assessment (LCA) methodology. From an analysis of the whole plant we observed that the highest environmental impact was caused by energy consumption, especially at the reverse osmosis stage, while the most relevant waste was brine. From an analysis of brine final disposal we have elaborated a comparison of the advantages and detriments of the three alternatives. As all of them might be suitable in different specific situations, the results might be useful in decisions about final brine disposal.

Uso de biodiesel en la biorremediación de derrames de petróleo crudo

El biodiesel es un combustible basado en esteres metilicos de acidos grasos con numerosas ventajas ambientales. Una de las mas importantes es su elevada biodegradabilidad y su habilidad para disolver el petroleo crudo. En este estudio, se prepararon mezclas de petroleo crudo pesado y biodiesel y se midieron las densidades y viscosidades de dichas mezclas con el fin de evaluar la facilidad de recoleccion de las mismas en una zona afectada por un derrame. Se encontro que la densidad de todas las muestras estaba por debajo de la densidad del agua de mar, lo que indica que estas flotaran en la superficie. La viscosidad de las mezclas fue inferior varios ordenes de magnitud con respecto a la viscosidad del petroleo crudo pesado; esto indica la posibilidad de bombear facilmente las mismas. Adicionalmente, se estudio la biodegradabilidad de las mezclas mediante el metodo de evolucion de CO2. En todos los casos, la biodegradabilidad se incremento con la adicion del biodiesel y mostro la presencia de efectos sinergicos debidos a cometabolismo. La mezcla, que contenia 50 % de petroleo crudo, demostro el mayor efecto sinergico. Finalmente, se plantearon diversas soluciones para el tratamiento de aguas y suelos afectados por un derrame de petroleo crudo pesado.